PROJECT SUMMARY/ABSTRACT Every year, million infants are born prematurely in the US and 15 million worldwide. Almost all preterm infants suffer from abnormal brain maturation resulting from interactions between brain immaturity and an atypical early extra uterine experience. At discharge to home they often have altered reactivity to sensory experiences in the home, associated with worse developmental outcomes in childhood. To improve these outcomes, it is critical to intervene in neonatal period when plasticity and cascading effects have the greatest potential. The need exists to design rigorous, standardized and mechanistically-based multisensory interventions leveraging parent support, in order to improve measurable multisensory neural processing in the neonatal period, with downstream effects on sensory reactivity in the home and better language and motor outcomes in early childhood. The overarching goals of this proposal are therefore tovalidate a safe, dyad- centered therapy constructed with easily available technology and parent-derived stimuli, adaptable to a wide variety of neonatal environments. To accomplish this, we propose a randomized controlled trial with intent-to-treat analysis in 200 hospitalized preterm infants between 32 and 36 weeks' post-menstrual age. The multisensory intervention, which includes 12 sessions of standardized, therapist-administered, auditory-tactile stimulation, and combines contingent recorded mother's voice delivered using a pacifier-activated system during holding with supportive tactile containment against the therapist's chest. Our approach incorporates an easy-to-use FDA approved pacifier- activated device to play parents' voice in response to infant suck on a pacifier. The containment hold approximates a care approach shown to improve muscle function, infant neuroregulation, parent-infant bonding, and deep sleep. The intervention group will receive the treatment in addition to monitored standard care. The contrast group will receive only monitored standard of care (i.e., skin-to-skin care by parent and daily sessions of parent's voice recording exposure). Multi- and uni- sensory neural processing will be measured at entry into the study and after the treatment phase, using novel event-related potential (ERP) assessments, as they are rapid and non-invasive, requiring neither active participation nor directed attention. Sensory reactivity will be measured at 1 year. Language and motor outcomes will be tested at 2 years. The short-term objective of this proposal is to directly test the hypothesis that multisensory treatment affects neuro-developmental outcomes through its effect on multisensory processing. We will also obtain quantitative and mechanistically relevant information on group response to treatment to help optimize future intervention designs and implement them in multiple neonatal care settings where parents cannot continuously be present at their child's bedside.